Chimney flue



Feb. 5, 1929; 1,700,850

R. J. MOTHS CHIMNEY FLUE Original Filed Feb. 9, 1927 I N VEN TOR.

A TTORNEYS.

Patented 'Feb. 5, 1929.

ire srrss rTNr OFFICE.

RAYMOND J. MOTHS, 01E MILWAUKEE, WISCONSIN.

CHIMNEY FLUE.

V Continuation of application Serial No. 166,953, filed February 9, 1927. This application filed September 30, 1927.. Serial No.'223,093.

lhis invention relates to improvements in chimney flues.

It is a well known factthat a round flue opening has a far higher co-eflicient of flow than in an opening of like cross sectional area but of a shape other than round. Actual tests by a large heating corporation have indicated an average increase of 40% in the draft through a round flue over that through a square flue. An attempt has been made to use round flue linings in chimneys, but has not metwith favor on the part of the masons who find it diiiicult to keep the chimney facing perfectly square with nothingother than a cylindrical flue tile to guide them.

I am aware of the fact that efforts have heretofore been made to produce a tile having a central flue which is round in cross section and an exterior surface which lends itself to square or rectangular designs for the guidance of the mason who lays the facing brick. Such attempts, however, have proven gen erally unsatisfactory either from the standpoint of expense or breakage.

lit is the object of the present invention to provide a novel and simple chimney tile having a square or rectangular'exterior and an interior flue passage which is round or at least curvilinear in cross section, the tile being so designed as to involve the use'of a minimum quantity of material to obtain a maximum degree of strength. It is also my purpose to provide chimney tile in units of such form and size as to be adapted for convenient handling. lhis is a continuation of application No. 166,953, filed February 9, 1927.

In the drawings: 1

Figure 1 shows in perspective an improved chimney tile embodying this invention projecting from a partially completed chimney structure, illustrating the application of facing bricks about the improved tile.

Figure 2 is a plan View of the tile. Like parts are identified by the same reference characters throughout the several views.

An improved tile embodying this invention preferablycomprises unitarily a flue member 1 which is round in cross section and of any suitable length, and a shell 2 which is rectangular or square in outline. In fact, it consists of around tube integrally formed within a square tube.

It is very important to note that the flue member 1 and shell 2 are not separate and distinct elements. The wall of the flue member will be observed to merge integrally with the wall of the shell 2 at each of the sides of the tile as shown at 3. At this point the thickness of the wall will preferably be no greater than the thickness of either of the walls separately. The inner periphery of the rectangular shell is tangent to the inner periphery of the flue and the same relation exists between the outer peripheries of the shell and flue. In no case should the wall at the point of juncture exceed twice the thickness of either wall alone and in fact it will be found to be impractical to exceed one and one-half times such thickness.

In the preferred construction illustrated the walls are so far merged to a single thickness that they completely lose their individual identity and the article as viewed in plan may be considered either as a rectangle with arcu'ate sectors applied across its inner corners or as a circle with angular corner pieces applied to its outer periphery. Square cormore in the flue make eddy currents which interrupt the tendency of the gases to flow helically and smoothly therethrough. llhe rounded interior permits of efficient flow and tends to eliminate accumulation of soot, while the square cornered exterior makes the tile practical and the particular form of the tile whereby the curvilinear Walls merge with eliminate surplus material which would be used if the flue passage were spaced more distantly from the outer "surface of the tile and to minimize breakage such as would occur if the walls were/thinner or thicker. A thinner wall would be subject to breakage by reason of its attenuation, and a thicker wall would be subject tobreakage bothbecause of the irregularity of cross section and because of the unevenness with which heat would strike. the tile in the kiln. The fact that the walls of the flue passage 1 merge symmetrically with the walls of the shell 2, likewise contributes greater strength than would be possible if these walls were spaced apart by any interposed medium.

It will be noted that in the corners of the shell 2, between the shell and the flue passage 1, are open spaces 4 of roughly triangular cross section. The existence of these spaces not only lightens the tile by the removal of the material which would otherwise be concentrated at these corners, but also makes possible several alternative constructions of value. For example, the spaces 4 may be utilized for ventilating passages, being reached at any desired point by openings cut through the tile into the desired spaces. They may also be used to receive re-enforcement where such a construction is necessary or desirable. Even after the chimney is completed it is possible to position re-enforcing bars in the vertical passages 4 and to fill such passages with concrete or mortar. It is also important to note that if the corners of the article were composed of a heavy mass of clay, there would be a tendency for the tile to heat unevenly in the kiln and to crack.

As hereinbefore suggested, it is preferred to construct the tile of suitable clay pressed through a die to the form illustrated and subsequently treated in a kiln to render it suit-' able for chimney flue purposes. Clay is the most desirable substance for a flue because of its high resistance to disintegration by water and acids in the flue gases. Other attempts to make a flue lining having a round flue portion and a rectangular facing have usually involved an attemptto use concrete because of the impossibility of forming clay in the designs which such attempted flue linings have incorporated heretofore. Concrete isnot a'desirable flue lining, because it is subject to disintegration by acids in the flue gases.

My tile may be encased in a facing of brick as shown at 5 in the drawing. The tile illustrated is known as twelve inch tile and standard brick may be laid up about its shell portion in the pattern indicated. It will be observed that my tile obtains the largest ratio of circular flue area to the total cross sectional area of the tile possible with a given wall thickness.

I claim:

1. A clay chimney tile comprising a flue portion having a curvilinear wall and a shell portion having a rectangular wall, said walls being merged at all four sides of said shell portion to a thickness not exceeding the thickness of one of said walls.

2. A clay chimney tile comprising integrally a fine portion and a shell portion, the outline of said shell portion being substantially rectangular, and said flue portion including walls extending across the corners of said shell portion and merging with contiguous sides thereof, the walls of the shell portion and the walls of the flue portion being of substantially uniform thickness equal to the minimum thickness at the point of merger.

3. A cla chimney tile comprising a shell having wa ls conforming substantially to the outline of an open square, in combination with a wall of substantially circular cross section formed within said shell and merging integrally with the walls of said shell at the sides thereof While spaced therefrom at its corners, the projected inner and outer surfaces of said square wall being substantially tangential to corresponding surfaces of said circular walls.

4. A clay chimney tile comprising a shell having walls of substantially uniform thickness conforming substantially to the outline of an open square, in combination with a tubular wall of like uniform thickness and substantially circular cross section formed within said shell and merging integrally with thewalls ofsaid shell at the sides thereof while spaced therefrom at its corners. the minimum thickness of said walls at the points of merger being substantially equal to the thickness of each individual wall whereby the internal .cross sectional area of said tubular wall bears a maximum ratio to the total area of said tile while preserving as nearly as possible uniform wall thicknesses throughout.

RAYMOND J. MOTHS 

